IN 6000 miles of coastline, the people of Britain have inherited a most magnificent natural asset. And nowhere can this be better experienced than in the North-east of Scotland.

On a bicycle journey covering part of that coast I discovered some of its secrets.

My starting point was Perth and whether you're a cyclist or a driver there's no need to stick to the A85 trunk road to Dundee since there's the pleasant B958 skirting the shore of the Firth of Tay via the village of Errol.

Dundonians may well sniff at their city's ''jute, jam and journalism'' tag since it does their city an injustice. It completely ignores their skills in the field of shipbuilding - sleek clippers for the India run and whalers for the Arctic commemorated for all time by the preservation of the Discovery and the frigate Unicorn, the oldest British-built ship still afloat. The rail bridge across the Tay is famed for more sombre reasons while outlying areas such as Broughty Ferry and Monifieth, and towns north of the city such as Arbroath and Montrose have a delightful ambience.

All the way to Montrose coast-hugging by-roads will keep you off the A92 Aberdeen-bound artery, though this does take over the shoreline thereafter through beautiful countryside by way of harbours such as Johnshaven, Inverbervie and Stonehaven to Aberdeen (don't miss the dramatic ruins of Dunnottar Castle).

The A92 runs straight to Fraserburgh on the north-easternmost corner of ''the rump'' with the mostly one-lane A952 making a detour via Peterhead. However, the smaller A975 inserts itself between the main road and the coast passing through peaceful Newburgh and Cruden Bay with its cliffs riddled by smugglers' caves; John Buchan country where the ghost of Richard Hannay haunts one of the most evocative regions in all Scotland.

By a quirk of geography the north-facing Moray coastline is sheltered from the worst of the rain-bearing south-westerlies so that it remains dry and wind-free even when black clouds and gales sweep the inland hills. It is indented with fishing harbours such as Fraserburgh, Sandhaven, Rosehearty, Pennan, and Macduff. Between Rosehearty and Macduff the little-used B9031, a world away from the A98 which veers inland here, dips and plunges through a landscape of pure magic.

The morning I was there was one of sun and racing clouds; blackface ewes regarding me cynically as I passed and a curlew whistled up on the fell. A fox trotted by and disappeared into a clump of gorse - vivid yellow on a carpet of purple heather.

Across the estuary of the River Deveron and Macduff's older neighbour, Banff, displays its elegant Georgian face ringed by floral gardens with the imposing Duff House surrounded by parkland that emphasises to a visitor that the town is a Royal Burgh.

At Portsoy, I saw the oldest harbour on the Moray Firth and at Cullen, one of the most attractive of the coast's small resorts. Portnockie, Findochty and Buckie are fishing townships of grey or white-scrubbed fisher houses and well-filled harbours. At Fochabers is Baxters of Speyside Visitor Centre, a food factory that has become a considerable tourist attraction.

Much of the route to Elgin can be made by minor roads that skirt the sea and, later, the Spey river and its estuary of wide horizons. Elgin, the administrative centre of Moray, is a handsome town equipped with a striking if ruined cathedral, a preserved water mill, the Ladyhill Column and traffic that has to squeeze round both sides of the Muckle Cross.

Due north, on the small A941, lies Lossiemouth, a fine seaside town with a harbour and range of sand dunes plus the roar of Buccaneers from the RAF base here. Nearby is Kinloss attained via a skein of minor roads linking Hopeman and Burghead on promontories giving panoramic views across the Moray Firth to Easter Ross.

Both Elgin and Nairn sit astride the A96 but coastal lanes are legion; particularly fine are those to Fort George - described by James Wolfe (of Quebec fame) as ''the most considerable fortress in Great Britain'' - and, inland, the infamous battlefield of Culloden that remains the most emotional site in Scotland.

Taking the road through Nairn, I arrived in Inverness. It had rained as I left Perth and it rained again as I entered Inverness but in between the the weather, the countryside and the people were the most welcoming a traveller could desire.